Some common characteristics of twins
Developmental Lag in physical, mental, motor, and speech development. Twins tend to lag behind singletons of the same age. Lag in motor and speech development is also seen. This lag may be due to brain damage or to prematurity but it is more likely to be due to parental over protectiveness.
Twins tend to be smaller, age for age, than singletons. This is generally due to the fact that they are premature. They also suffer from brain damage and other physical defects more often than singletons.
Mental similarities between identical twins are much greater than between nonidentical twins and this persists into old age. Identical twins also show strong similarities in terms of special abilities, such as musical and artistic aptitudes.
Twins tend to compete for adult attention, to imitate each other's speech and behavior, and to depend on each other for companionship during the preschool years. As they grow older, sibling rivalry and competition develop. One twin usually takes on the role of leader, forcing the other into the role of follower. This affects their relationships with other family members and with outsiders.
Many twins have difficulty in developing a sense of personal identity. This is especially true of identical twins and of nonidentical twins of the same sex. Others enjoy the close relationship of twinship and the attention they receive as a result by their similarity in appearance. This leads to self-satisfaction and self-confidence.
Behavior problems have been reported to be more common among twins than among singletons of the same ages. It is thought that this is a result of the way twins are treated, both at home and outside the home. Behavior problems have also been reported to be more common among nonidentical than among identical twins. It has been suggested that this is because rivalry is stronger between nonidentical than identical twins.
It was interesting to read on the common characteristics of twins. Now let us analyse the three periods of prenatal development.
The prenatal period is ten lunar months of twenty eight days each in length or nine calendar months. This can vary from 180 to 334 days. Because prenatal development is orderly and predictable, it is possible to give a timetable of the important development taking place during this period. This period is divided into three stages.